Tapped P-90 Wiring Question

[Daver]

I don't make pickups but I have a question regarding a tapped P-90. I know you could wind a P-90 to say 8K and have a tap at say 6K and switch between them for different output levels and tone. If the full 8K winding was always connected to the output and you then also switched in the 6K tap would that short out the remaining 2K and function similar to the standard switching type or would that 2K of coil cause some other effect? Thanks.
Dave

[big_teee]

Hi Daver:
When You Split a coil, the normal way is to move the ground from the end to the tap in the middle.
So if you are using 2/3 of the coil, you have the output on one end and ground the coil at the 2/3 point.
The unused portion of the coil is grounded at the 2/3 pos.
That portion of the coil is just hanging there with resistive ground on it.
Same principal for tapped buckers and single coils.
Here is a Seymour duncan layout for a Tele, it would also apply for a Tapped P90.
Wiring Diagram
Follow the output and the ground on the layout, and you will see how they do it.
It works great!
Good Luck,
Peace, N Volume!
T

[Daver]

Big Teee,
In that drawing they aren't changing the ground of the coil, just switching between two taps. I understand how that works. Anyway, that really wasn't my question. The single coil pickups I've used that had taps (Tele) had the ground connnection constant and switched between the full coil tap and one somewhere at a point less than the full coil. That's pretty much how that Duncan layout you linked works. My question is rather than switching between those two point in the coil, if you leave the full coil tap always attached to hot but then also switch in the lower DCR tap (2/3 or what have you) will that give you the same effect as disconnecting the full coil tap when using the other tap? Hopefully I didn't make that more confusing. Thanks!
Dave

[big_teee]

Big Teee,
In that drawing they aren't changing the ground of the coil, just switching between two taps. I understand how that works. Anyway, that really wasn't my question. The single coil pickups I've used that had taps (Tele) had the ground connnection constant and switched between the full coil tap and one somewhere at a point less than the full coil. That's pretty much how that Duncan layout you linked works. My question is rather than switching between those two point in the coil, if you leave the full coil tap always attached to hot but then also switch in the lower DCR tap (2/3 or what have you) will that give you the same effect as disconnecting the full coil tap when using the other tap? Hopefully I didn't make that more confusing. Thanks!
Dave

Yes that should work.
Just try it and see.
If you have a DPDT switch you should be able to remove the output from the unused portion of the coil.
Good Luck,
T

[RCI Guitars]

What I don't understand is the way the ground is connected 2/3 through the coil? I mean, clearly its a third wire that gets attached to an eyelet in the bobbin, but that ground is attached as the finish of the coil? is it just soldered to the coil wire at a certain point and when its switched becomes the ground to shut off the other 1/3 of the coil?

Please elaborate

[copperheadroads]

The start wire is grounded & to the first eyelet
The first tap @ say 6k is tied to the second eyelet & the new start is also tied from this point
The final finish end is soldered to the 3rd (added eyelet)
Here's a pic of a tapped steel pole tele I wound (You can't see the second start wire in the pic ,It's hiding behind the yellow wire )
Ground the original start & switch between the 2 finish wires

[RCI Guitars]

Okay!! That makes sense. So basically, your winding the coil to say 6k and then tying it off to eyelet #2 and then starting a second wind on top of the existing winds starting at eyelet #2-winding to 8.7k or whatever you want the final resistance to be and then finishing on eyelet #3.
Thank you for clearing that up for me

[big_teee]

I tried the tap a couple of times, and everyone just played the pickup on the highest DCR.
It looks cool though.
T

[Stratz]

You can use different types of the same gauge wire as well.
I've made them with 42 PE for the main coil and 42 HF for the secondary and vice versa.

On a Strat bobbin I like to go about 5.6K to ~ 6.5K. Two very different sounds.

Rob.

[copperheadroads]

On the steel pole tele I did in the pic ,The first tap was @ 7.8k of 42 gauge wire the second tap was to 9k & I used 43 gauge wire to the customers request ,It was a little more than 1000 turns probably 1200.
& the tone difference is not really that great ,I was supprised how little the extra winds changed the tone

[Ward]

I did a tapped humbucker years ago, honestly couldn't hear a difference, never did it again.